This invention generally relates to the art of electrical connectors and, particularly, to a card edge connector assembly for electrically connecting at least a pair of stacked memory cards.
Memory modules, or memory cards have been used extensively due to the need for high memory capacity in computer systems and other applications. Connectors for such memory cards typically are mounted on a circuit board, such as a motherboard. In order to increase capacities, such connectors often are stacked on top of each other to conserve space or xe2x80x9creal estatexe2x80x9d on the circuit board.
For instance, FIG. 1 illustrates a tandem edge card connector assembly, generally designated 10, for receiving two memory modules or cards, as disclosed in ROC Patent No. 370290. The connector assembly includes a lower connector 12, and an upper connector 14 that overlies the lower connector. The lower and upper connectors receive a pair of stacked memory or edge cards 16 and 18, respectively.
More particularly, lower connector 12 includes a housing 20 mounting a plurality of conductive terminals 22 along an elongated slot 24. A pair of arms 26 project forwardly of housing 20 at opposite ends of slot 24.
Although not shown in FIG. 1, it is well known that the terminals 22 are designed for receiving a memory card, such as lower memory card 16, at an angle with zero insertion forces. The memory card is then tilted or rotated downwardly so that the terminals apply pressure to the conductors on the memory card. In FIG. 1, it can be seen that memory card 16 is at an angle for insertion into slot 24 of housing 20 of lower connector 12. Once fully inserted into the slot, the memory card 16 is rotated downwardly until notches 28 in opposite side edges of the card 16 interengage with the bosses 30 that project inwardly of the arms 26. The memory card 16 then is held between the engagement arms in an orientation that is generally parallel to the circuit board on which connector assembly 10 is mounted.
The upper connector 14 also includes a housing 32 that supports a plurality of terminals 34 along a slot 36. A pair of arms 38 project forwardly of the housing 32 at opposite ends of the slot 36. As seen clearly in FIG. 1, the housing 32 has a downwardly offset portion 32a so that upper connector 14 nests on top of and behind lower connector 12, with arms 38 of the upper connector partially overlying arms 26 of the lower connector.
As with the lower connector, upper memory card 18 is inserted into slot 36 of upper connector 14 at an angle with zero insertion forces. The upper memory card then is tilted or rotated downwardly until notches 28 at opposite side edges of the card interengage with bosses 30 projecting inwardly from arms 38 of the upper connector.
Although electrical connector assembly 10 of the prior art allows insertion of two memory cards 16 and 18 therein, to conserve space on the circuit board, it can be seen in FIG. 1 that upper connector 14 is staggered above and rearwardly relative to lower connector 12. The upper connector 14 is shifted horizontally rearwardly so that arms 38 of the upper connector do not completely block arms 26 of the lower connector. This staggered relationship of the two connectors is required so that the upper memory card 18 does not interfere with lower memory card 16 when the lower memory card is inserted or removed from lower connector 12 while upper memory card 18 is fully inserted into upper connector 14. If the upper connector 14 was mounted directly on top of, or vertically aligned with lower connector 12, an inserted upper memory card 18 would make it difficult to remove the lower memory card 16 without possibly damaging one or both of the cards or it would require a user to remove the top edge card just in order to gain access to and remove or insert the bottom edge card. Therefore, prior art connectors as shown in FIG. 1 must have upper connector 14 shifted horizontally or staggered rearwardly relative to lower connector 12, as shown. The problem with such staggered arrangements is that connector assembly 10 takes up too much horizontal space or xe2x80x9creal estatexe2x80x9d on the circuit board. Additionally, the short heights of the connectors compared to the long lengths of the connectors, the length of the connectors must be extended a large distance in order to accommodate the rotational insertion/removal movement of the cards. This large space takes up space on the circuit board that could otherwise be used for other electronic components.
The present invention is directed to a stacked card edge connector assembly that overcomes the aforementioned disadvantages.
An object, therefore, of the invention is to provide a new and improved card edge connector assembly for electrically connecting at least a pair of stacked memory cards, such as on a circuit board.
Another object of the present invention is to provide an improved, stacked edge card connector assembly for mounting a pair of edge cards, in which the edge cards are mounted in a manner so that the insertion/removal of one of the two edge cards does not interfere with the insertion/removal of the other edge card.
A further object of the present invention is to provide a stacked edge card connector in which two card connectors are stacked on each other and are oriented with respect to each other at an oblique angle so that one of the two cards can be inserted or removed from its connector without requiring the insertion or removal of the other of the two cards.
In the exemplary embodiment of the invention, the connector assembly includes a lower connector having a dielectric housing supporting a plurality of conductive terminals along a slot for receiving an edge of a lower memory card. An upper connector is provided with a dielectric housing also supporting a plurality of conductive terminals along a slot for receiving an edge of an upper memory card at an angle to the lower memory card, the angle diverging in a direction away from the slots.
According to one principal aspect of the present invention, the housings and the respective slots of the lower and upper connectors are generally in vertical alignment above the circuit board. The lower memory card is received in the lower connector generally parallel to the circuit board on which the connector assembly is mounted. The angle of the upper memory card is inclined upwardly relatively to the circuit board. In the preferred embodiment, the assembly includes a one-piece connector body defining the two housings of both the lower and upper connectors.
According to another aspect of the invention, a pair of arms project from the housing of each of the lower and upper connectors at opposite ends of the respective slot thereof and between which the memory cards are inserted into the slots. The arms of the upper connector project at an angle relative to the arms of the lower connector. The arms are flexible, and a strain relief member is provided to limit flexing of the arms. The arms and the respective housings are fabricated of plastic material, and the strain relief member is fabricated of metal material and includes a foot portion for securing, as by soldering, to the circuit board.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.